Is time travel possible? Many physicists say maybe in the past but not in the future. Is this true?
In the spirituality forum there is a thread called free will. I often used the free will question to provoke thought from the Jehovah's Witnesses that would knock on my door. "If god knows knows what will happen in the future how can that be compatible with free will?" I would ask them.
If time travel into the future is possible then it seems as if there is not free will. If it is not possible then there is free will. That is my way of looking at it anyway.
Is time travel into the future possible? I tend to think no.
if time travel into the past is possible, it would beg the question of why we don't know of any evidence of time-travelling people from the future travelling to the modern times? I would expect such evidence. And then, of course, there is the problem of the time paradox. So I believe it to be unlikely that it is possible.
However, I speculate these two problems could be resolved and you could still have your time travel but only if one make certain assumptions that are extremely difficult to justify:
IF there are an infinite number of parallel universe which have very similar but not identical histories to our own and IF it is possible to travel from our universe to some but not all of the others because it is not possible to travel to some of them ( perhaps there can be some kind of 'one-way' wormholes connecting them ) and IF one of those universes that it is not possible to travel to from another universe is our own universe then that would explain why we don't know of any evidence of time-travelling people from the future travelling to the modern times and also you could also sort-of travel back into time by travelling to one of those other parallel universe ( that had a past almost identical to our own if not identical ) but to an earlier stage of it and do so without there being any time paradox.
That's some big ifs though.
Originally posted by Metal Brain Is time travel possible? Many physicists say maybe in the past but not in the future. Is this true?
In the spirituality forum there is a thread called free will. I often used the free will question to provoke thought from the Jehovah's Witnesses that would knock on my door. "If god knows knows what will happen in the future how can that be compatible ...[text shortened]... way of looking at it anyway.
Is time travel into the future possible? I tend to think no.
Questioning time travel is not necessary to show that free will is nothing more than a myth. Experiments in the 70s have shown that when you make a decision to move a body part, the decision was already made in your brain 200 milliseconds before the action. It's pretty much the religious who refuse to believe science.
Originally posted by amolv06 If by time travel into the future you mean you experience 10 seconds, whereas the rest of the earth experiences 10 years, then it is possible.
Originally posted by Phil Hill Questioning time travel is not necessary to show that free will is nothing more than a myth. Experiments in the 70s have shown that when you make a decision to move a body part, the decision was already made in your brain 200 milliseconds before the action. It's pretty much the religious who refuse to believe science.
That does not disprove free will. I'm interested in disproving fatalism, not free will. I don't believe time travel into the future is possible. Probably not in the past either.
Originally posted by Metal Brain That does not disprove free will. I'm interested in disproving fatalism, not free will. I don't believe time travel into the future is possible. Probably not in the past either.
How does it allow room for free will when it shows your decisions are not freely chosen by you but made by your brain between 200-500 milliseconds before you do them?
As far as time travel, for elementary particles it happens all the time (into the past) and "time standing still" for photons and other particles traveling at c.
Originally posted by Metal Brain No, that is relativity. That is not time travel.
"Time travel" is possible in a relativistic sense, but not in any other way. Relativity says that causal influences, or "information", cannot travel faster than light.
Originally posted by KazetNagorra "Time travel" is possible in a relativistic sense, but not in any other way. Relativity says that causal influences, or "information", cannot travel faster than light.
Just thought I would bring up entanglement since you brought up information being restricted to light speed. The speed limit still holds since the entanglement may be non-local but to convey the information, the observer at point B must transmit the information to point A via conventional methods that are subject to light speed as a limit.
Originally posted by Phil Hill How does it allow room for free will when it shows your decisions are not freely chosen by you but made by your brain between 200-500 milliseconds before you do them?
As far as time travel, for elementary particles it happens all the time (into the past) and "time standing still" for photons and other particles traveling at c.
Light from the sun doesn't reach Earth until about 8 minutes. So what!
What does that have to do with free will? Nothing!
As far as time travel, for elementary particles it happens all the time (into the past) and "time standing still" for photons and other particles traveling at c.
Time standing still is not time travel. Please show me your source of information showing elementary particles travel into the past.
Originally posted by Metal Brain Time standing still is not time travel. Please show me your source of information showing elementary particles travel into the past.
What do you think anti-particles are? You might want to look up the work of R. Feynman.
Now please tell me how the experiment I mentioned allows for free will?
Time standing still most certainly is a type of time travel, so is everything that was mentioned in this thread. You seem to be under some false impression that the only kind of time travel is the crap you read in science fiction magazines.
BTW, if the state of any system is known. The past as well as the future can be predicted with 100& accuracy. It's just in practice we have trouble computing anything with so many variables. IOW, everything is predetermined.
Originally posted by Phil Hill BTW, if the state of any system is known. The past as well as the future can be predicted with 100& accuracy. It's just in practice we have trouble computing anything with so many variables. IOW, everything is predetermined.
That's not really a question that physics can answer definitively. Although any system whose Hamiltonian is known evolves in time deterministically, it's not well-understood how wave function collapse takes place and whether it is fundamental to nature or something emergent from deterministic systems.
Originally posted by KazetNagorra That's not really a question that physics can answer definitively. Although any system whose Hamiltonian is known evolves in time deterministically, it's not well-understood how wave function collapse takes place and whether it is fundamental to nature or something emergent from deterministic systems.
Sure it is. If the state of a system is known with 100% accuracy, the past as well as the future evolution can be determined. If you don't believe that is an accurate statement, you can go to CalTech and argue over there.
Time travel/free will
17 Aug '12 17:56
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